Aircraft Observation Research on Macro- and Microphysics Characteristics of Continental Cumulus Clouds at Different Development Stages

Weather Modification Office of Shanxi Province organized an in-situ observation through continental cumulus clouds for the first time on 3 July 2014 in China. Based on the airborne cloud physical data, macro and microphysical properties of continental cumulus cloud at different development stages were analyzed. The main results: (1) For growing cumulus, the horizontal scale is about 8.2 km×5.5km (meridional direction×zonal direction, the same hereinafter) and cloud depth is 2 km. The cloud is dominated by small particles, which gradually grow through the condensation process. The maximum cloud water content (LWC) and particle number concentration (N_c) appear at the horizontal direction of cloud center. In the vertical direction, N_c decreases and particle effective diameter (ED) increases with height, while LWC distribution is uniform. The particle spectrum is consistent with gamma distribution, and the peak magnitude is 10² cm⁻³ μm⁻¹, where the spectral width is less than 100 μm. (2) For mature cumulus, the horizontal scale is about 4.6 km×10 km and cloud depth is 4 km. The ice and rain lines can be seen in the cloud. N_c varies with height, with three peaks occurring at heights of 3600 m, 4100 m, and 4900 m. The concentration of large cloud particles initially increases first and eventually decreases with height. The maximum value appears at a height of 1.6 km above the bottom of the cloud. Precipitation particles can be formed near the height of 1.3 km above the cloud base. The particle spectrum is multimodal. The spectrum can be described as a gamma distribution in the warm cloud region. In the cold cloud region, the spectrum is mostly a combination of gamma distribution and M-P distribution. The particle spectrum broadens with increasing height, and the spectral width is less than 200 μm below 4400 m. (3) For dissipating cumulus, the horizontal scale is about 5.6 km×11 km and cloud depth is 2 km. Precipitation particles are present under the cloud.